Combustion apparatus



Nov. 3, 1936. D. F. KILGOUR COMBUSTION APPARATUS Filed Sept. 9, 1931 AMJPatented Nov. 3, 1936 UNITED STATES PATET OFFICEN 3 Claims.

My invention relates to combustion apparatus, and more particularly, butnot exclusively, to boiler settings having provision for burning oil,pulverized coal, and similar fuels.

5.: This application is a continuation in part of application SerialNumber 488,254, led October 13, 1930 and renewed May 25, 1933, nowPatent 1,924,209.

The inventio-n will be best understood from the following descriptionwhen read in the light of the accompanying drawing of one embodiment ofthe invention selected for illustrative purposes, the scope of theinvention being more particularly pointed out in the appended claims.

In vthe drawing:-

Fig. l is a vertical section of a boiler setting with a fragment of theassociated boiler; and

Fig. 2 is a section on the line 2 2 of Fig. 1, with parts shown in plan.f

Referring to the drawing, the boiler setting illustrated has annularwalls comprising the outer brickwork I and an inner structure 3 ofrefractory clay or fire-brick. As shown, the outer brickwork is formedto provide an arcuate chamber 5, and an upwardly extending wall 1 ofreduced diameter upon the top of which rests the shell 5 of a boiler.The boiler, as illustrated, is of the lire-tube type, having thevertical nre-tubes I I for ascending products of combustion, and thereturn re-tubes I3 for descending products of combustion, the latterdischarging into a chamber I5 formed by the walls 1 and casing I1. Asshown, the chamber I5 communicates with a smoke-pipe I9 for leading theproducts of combustion to a stack.

As shown, the inner walls of the boiler setting are formed to provide afire-pot having the cylindrical lateral walls 2| and the upwardlyconverging roof 23, the latter being provided with an axial circularopening with which communicates an upwardly extending flue, the latterbeing circular in cross-section and having the upwardly and outwardlydiverging walls 21.

In the present embodiment of the invention, the arcuate air chamber 5extends almost completely around the fire-pot, and at one end thereofhas an opening 29 communicating with the atmosphere, while at its otherend it is provided with an opening 3l with which communicates thesuction pipe 33 of a blower 35, the latter being driven by any suitablemeans as, for example, an electric motor 31. As shown, the dischargepipe of the blower communicates with the lire-pot the nre-pot. 43 forfuel oil.

As a result of the above described construction, air is drawn throughthe opening 29 into the arcuate chamber 5 in which said air is heated,the hot air being discharged through the pipe 39 into the nre-pot, whileoil is drawn from the nozzle 43 by ejector action and atomized and mixedwith the hot air to form a combustible mixture. The ignited combustiblemixture in the nre-pot is given a whirling motion due tol the eccentricarrangement of the pipe III, being held in the repot for an appreciabletime due to this mo-tion and the restricted nature of the opening 25.Passing through the opening 25 the combustible mixture enters theupwardly flaring flue 21, continuing its whirling motion, and risingslowly and expanding in the flue due tothe increasing cross-sectionalarea of the latter. Due to this action the products of combustion arecontinuously intimatelyv mixed while combustion is taking place, withthe result that the fuel is completely consumed. The products ofcombustion pass from the flue 21 into the fire-tubes I I and thenthrough the return tubes I3 to the chamber I5 and pipe I9. It has beenfound that best results Will be secured when the circular opening in thefire-pot roof is in the nature of a relatively sharp edge as shown inthe application drawing. In practice however this edge need not be aline in the geometrical sense of the word, but should not constitute anopening of material length axially thereof, because in such case theproducts of combustion would be directed by the opening axially of thediverging ilue, which would prevent eiective utilization of the latterin respect to mixing the gases and securing complete combustion. It willbe observed that the upwardly traveling whirling gas in the fire-potadjacent the roof thereof is guided toward the opening 25 by theupwardly converging walls of said roof, which causes each particle ofthe gas as it leaves the fire-pot to be directed upwardly and across theue 21. For example, if the gaseous products in contact with the upwardlyconverging wall in the fire-pot roof 23 at the left hand side of Fig. 1are considered, when they reach the opening 25 they immediately travelover toward the right hand side of the upwardly diverging ilue 21. Asthis occurs at all points around the circumference of the opening 25,spreading and intimate mixture of the gas take place in the upwardlydiverging ue 21 as soon as the gas enters it. Ii the opening 25 were ofmaterial length axially thereof, the whirling gases discharging from theopening into the upwardly Interiorly of the pipe 35 is a nozzlediverging flue 21 would be directed vertically upward and would notimmediately spread, and as a consequence the effect of the flue 21 wouldbe materially diminished in respect to securing complete combustion.

I have found that perfect combustion may be secured under favorableconditions by use of the throated, upwardly ilaring flue provided by thecentral circular opening 25 in the roof of the firepot and the divergingwalls 21, provided the flue is of suiiicient length, which length formany installations would make the boiler setting of prohibitive height,especially where the boiler setting is used with a vertical boiler orother boiler having considerable height. I have found, however, that thelength of this flue may be-materially reduced without sacrifice ofcombustion efficiency by giving the products of combustion a whirlingmotion as they pass through the throat of the flue. As a result of thisreduction in length of the flue, the height of the boiler setting may bematerially reduced, making it practical to employ the throated flue inmany situations where it would otherwise be impossible to do so, thisreduction in height of the boiler setting having the further advantagethat its construction involves less material and labor costs.

It will be understood that within the scope of the appended claims widedeviations may be made from the form of the invention herein described.

I claim:

1. Apparatus of the character described having, in combination, afire-pot, a relatively long upwardly relatively slowly flaring ue ofrelatively large cross-sectional area for conducting combustion productsfrom said fire-pot, and means for delivering mixed air and fuel to saidfire-pot transversely and eccentrically thereof to cause a whirling ofthe combustion products therein about its axis prior to delivery to saidflue,

said ilaring flue communicating with said fire-pot through an openingformed in the fire-pot roof of suiiciently short length axially thereofto permit substantially immediate spreading of the whirling products ofcombustion as they enter said flue.

2. A furnace having, in combination, a lire-pot the roof of which isformed with a central opening, said fire-pot having substantiallycontinuously transversely curved interior lateral walls, a flue havingupwardly relatively slowly diverging interior lateral walls of roundedcross-section in horizontal planes, which ue communicates with saidCentral opening, and fuel nozzle means for delivering fuel to saidfire-pot and directing it against said interior lateral walls thereof atone side of the axis of the same for causing a whirling of combustionproducts therein prior to delivery to said opening, said central openingbeing of sufliciently short length axially thereof to permitsubstantially immediate spreading of the whirling products of combustionas they enter said flue.

3. A furnace having, in combination, a re-pot the roof of which hasupwardly relatively quickly converging walls, said fire-pot havingsubstantially continuously transversely curved interior lateral walls, aflue having upwardly relatively slowly diverging interior lateral wallscommunicating with said fire-pot through a central circular openingformed in said roof of relatively short length axially thereof, saidinterior lateral walls of said re-pot and iiue being of circularcrosssection in horizontal planes, and fuel nozzle means for deliveringfuel to said fire-pot and directing it to impinge against said lateralinterior walls thereof at one side of the axis of the same for causing awhirling of combustion products therein prior to delivery to saidcircular opening.

DWIGHT F. KILGOUR.

